JP5287363B2 - Drilling system - Google Patents

Description

The present invention also relates to a drilling system for the construction of cast-in-place pile.

  Conventionally, the ground is drilled with an excavator and a rebar cage is built in the excavation hole, and concrete is placed in the excavation hole while filling the excavation hole with a stabilizing liquid to protect the hole wall. The method of building cast-in-place piles is used. At this time, it is necessary to collect muddy water in which the excavated sediment is mixed with the stable liquid from the inside of the excavation hole, and supply an amount of the stable liquid corresponding to the collected amount into the excavation hole to circulate the stable liquid.

  As shown in FIG. 5A, the stabilizing liquid is circulated to the bottom of the excavation hole 11 through the pipe 242 in the rod 241 of the excavator 240 as shown in FIG. A normal circulation system in which the muddy water overflowing into the pit 12 is recovered by the pump 236, and the muddy water from which the earth and sand has been removed is supplied again as a stable liquid into the borehole 11, and as shown in FIG. There is known a reverse circulation system in which muddy water is collected from the tip of the bit 243 of 240, and the earth and sand removed from the collected muddy water is supplied as a stable liquid into the excavation hole 11 from the ground surface.

  Further, for example, Patent Document 1 describes a circulation excavator capable of switching between such a normal circulation method and a reverse circulation method. According to such a circulation excavator, when the sediment in the drilling hole is discharged through the rod by the reverse circulation method, when the sediment is clogged in the rod, the inside of the rod is stabilized by switching to the normal circulation method. Since the liquid flows backward, the clogged earth and sand can be removed without lifting the rod.

JP 2008-75287 A

  Here, in both the normal circulation method and the reverse circulation method, the sand pump discharges earth and sand together with the stabilizing liquid from the drilling hole. However, if the distance between the sand pump and the drilling hole becomes longer, the sand pump removes the sand from the drilling hole. There is a tendency that voids are likely to occur in the pipe to the pump. As described above, if air enters the pipe connected to the sand pump, the suction force is reduced. Therefore, conventionally, it has been necessary to install the sand pump in the vicinity of the excavation hole.

  However, in the case of construction on a narrow site such as construction on a railway track, it may be difficult to install a sand pump near the excavation hole. Moreover, when constructing a plurality of piles, it took a lot of time to install and remove the sand pump, and there was a problem that workability deteriorated.

  This invention is made | formed in view of said problem, The objective is to enable it to install a sand pump in the position spaced apart from the excavation hole, when constructing a cast-in-place pile.

The excavation system of the present invention includes an excavator that drills the ground to form an excavation hole, a stable liquid treatment plant that processes the recovered mud water to purify the stable liquid, and a stable liquid from the stable liquid treatment plant. Constructing a cast-in-place pile comprising a mud feed pipe that is fed into the excavation hole, and an exhaust mud pipe that is provided with a suction pump in the middle and sends the stabilizing liquid in the excavation hole to the stabilizing liquid treatment plant A drilling system for drilling a drilling hole when the mud feeding pipe is connected to the excavator and the drainage pipe is connected to the drilling hole; It is connected to the wellbore with the waste sludge pipe circulation switching device capable of switching between a state of being connected to the excavator, between the suction pump and the circulation switching device of the waste sludge pipe A branch pipe is connected to the top, and The branch pipe is connected with the suction port of the jet pump, which is supplied with compressed air from a compressor and blows the compressed air in one direction to generate an air flow from the suction port to the discharge port. It is characterized by.

  According to the present invention, air in a pipe connected to a sand pump can be removed by a jet pump. Thereby, the fall of the attraction | suction force of a sand pump can be prevented and a sand pump can be installed in the position spaced apart from the excavation hole.

It is a figure which shows the structure of the excavation system of this embodiment. It is sectional drawing which shows the structure of a jet pump. It is a figure which shows the excavation system in the case of circulating a stable liquid normally. It is a figure which shows the excavation system in the case of circulating a stable liquid backward. (A) shows the excavation method by a normal circulation system, (B) is a figure which shows the excavation method by a reverse circulation system.

Hereinafter, an embodiment of the excavation system of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the excavation system 10 according to this embodiment includes an excavator 40, a stable liquid treatment plant 20, and a piping system 100 that connects the excavator 40 and the stable liquid treatment plant 20. The

  The excavator 40 includes an excavator main body 41 installed on the ground surface, a rod 42 to which a excavation bit 43 is connected at the tip, and a pipe 44 is inserted through the inside, and a rotation mechanism 45 that rotates the rod 42. . The excavator 40 excavates the ground with the excavation bit 43 attached to the tip of the rod 42 by arranging the excavator main body 41 on the ground and rotating the rod 42 by the rotation mechanism 45. In the present embodiment, the excavator 40 having the rotation mechanism 45 at the upper part of the excavator body 41 is used. However, the excavator 40 having the rotation mechanism 45 at the lower part of the excavator body 41 may be used.

  The stable liquid treatment plant 20 is supplied with the muddy water collected from the borehole 11 through the piping system 100, and again supplies the mudwater from which the earth and sand have been removed to the borehole 11 through the piping system 100 as a stable liquid.

  The piping system 100 includes a circulation switching device 30, a first piping system 110 that connects the stabilizing liquid treatment plant 20 and the circulation switching device 30, and a second piping system that connects the circulation switching device 30 and the excavator 40. 120.

  The first piping system 110 stabilizes the plant-side mud feed pipe 111 that sends the stable liquid from which the sediment has been removed in the stable liquid treatment plant 20 to the circulation switching device 30 and the stable liquid containing the earth and sand from the circulation switching device 30. It is comprised by the plant side waste mud piping 112 sent to the liquid processing plant 20. FIG. A pump 114 for pressure-feeding the stabilizing liquid is attached to an end of the plant-side mud feeding pipe 111 on the side of the stabilizing liquid processing plant 20. Further, a sand pump 113 for sucking muddy water is attached in the vicinity of the end of the plant side mud pipe 112 on the side of the stabilizing liquid treatment plant 20.

  Further, a branch pipe 150 is provided between the circulation switching device 30 of the plant side mud pipe 112 and the sand pump 113, and a jet pump 151 is connected to the branch pipe 150. A compressor 152 is connected to the jet pump 151, and compressed air is supplied.

  FIG. 2 is a cross-sectional view showing the configuration of the jet pump 151. As shown in the drawing, the jet pump 151 includes a body portion 170 formed in a conical shape whose diameter gradually decreases from the suction port 161 side toward the discharge port 160 side. The branch pipe 150 is connected to the suction port 161. An annular injection chamber 172 is formed on the body portion 170 on the suction port 161 side, and compressed air is supplied to the injection chamber 172 from the compressor 152 through the air supply port 171. Between the injection chamber 172 and the internal space 174 of the trunk | drum 170, the ventilation port 173 which becomes narrow toward the internal space 174 is formed. The compressed air supplied to the injection chamber 172 is injected into the internal space 174 in a state where the momentum is increased by passing through the ventilation port 173. As a result, an air flow is generated in the jet pump 151 from the suction port 161 side to the discharge port 160 side.

With this configuration, the jet pump 151 can suck fluid from the suction port 161 side and inject it to the discharge port 160 side.
The second piping system 120 is provided so as to connect the first apparatus side pipe 130 provided so as to connect the circulation switching device 30 and the excavator 40, the excavation hole 11, and the circulation switching device 30. 2 device-side piping 140. The first apparatus side pipe 130 is connected to the excavator 40 via a swivel joint (not shown).

Hereinafter, a ground excavation method using the excavation system 10 will be described.
First, the ground is excavated to form an excavation hole while the stabilizing liquid is normally circulated. When the stabilizing liquid is normally circulated, as shown in FIG. 3, the closing valves 36 and 37 attached to the switching pipes 33 and 34 of the circulation switching device 30 are closed and the closing valves attached to the pipes 31 and 32 are closed. The valves 35 and 38 are opened, and the pump 114 and the sand pump 113 are activated. At the same time, the compressor 152 is activated to supply compressed air to the jet pump 151.

  When compressed air is supplied to the jet pump 151, the jet pump 151 sucks the air in the plant-side waste mud pipe 112 through the branch pipe 150 and releases it to the outside. As a result, the inside of the plant-side mud pipe 112 can be brought close to a vacuum state, and the suction force of the sand pump 113 is improved. Therefore, even if the distance between the sand pump 113 and the excavation hole 11 is large, the sand pump 113 enables the muddy water in the excavation hole 11 to be sent to the stable liquid treatment plant 20.

The supply of compressed air to the jet pump 151 by the compressor 152 is stopped after confirming that the air in the plant-side mud pipe 112 has been sufficiently discharged. The fact that the air has been sufficiently discharged includes, for example, (1) a method of visually confirming that the stable liquid is discharged from the discharge port 160 of the jet pump 151, and (2) the pressure in the plant-side mud pipe 112. To confirm that the pressure has been reached, (3) manage the time from the start of the compressor 152, and check the method by starting the compressor 152 until the time from the start reaches the predetermined time can do.
In this way, the excavation hole 11 is excavated to a depth corresponding to the lower end of the cast-in-place pile while the stabilizing liquid is normally circulated.

  When the excavation hole 11 has been drilled to a depth corresponding to the lower end of the cast-in-place pile, the rotation of the bit 43 of the excavator 40 is stopped and the pump 114 and the sand pump 113 are stopped once. Then, after switching the circulation switching device 30, the pump 114 and the sand pump 113 are activated again to reversely circulate the stabilizing liquid.

  As shown in FIG. 3, when the stabilizing liquid is reversely circulated, the closing valves 36 and 37 attached to the switching pipes 33 and 34 of the circulation switching device 30 are opened, and the closing valves attached to the pipes 31 and 32 are opened. The valves 35 and 38 are closed, and the pump 114 and the sand pump 113 are activated. At the same time, the compressor 152 is activated to supply compressed air to the jet pump 151.

  Thereby, similarly to the case of the normal circulation, even if the distance between the sand pump 113 and the excavation hole 11 is largely separated, the mud water in the excavation hole 11 can be sent to the stable liquid treatment plant 20 by the sand pump 113. .

  Thus, the slime collected at the bottom of the excavation hole 11 can be discharged by reversely circulating the stabilizing liquid.

  As described above, after the reverse circulation is performed for a predetermined period, the excavator 40 is removed, and the rebar cage is inserted into the excavation hole 11. Then, concrete is placed in the excavation hole 11 through a treme tube. Construction of cast-in-place piles is completed when the cast concrete hardens.

  As described above, according to the present embodiment, the inside of the plant-side mud pipe 112 can be brought close to a vacuum state by discharging the air in the plant-side mud pipe 112 to the outside by the jet pump 151. Accordingly, it is possible to prevent the suction force of the sand pump 113 from being reduced due to the air remaining in the plant-side mud pipe 112, so that the sand pump 113 can be provided at a position away from the excavation hole 11. . Thereby, there is no restriction on the installation position of the sand pump 113, and the construction can be smoothly performed even in a narrow site.

  Moreover, when constructing a plurality of cast-in-place piles, conventionally, since the sand pump 113 had to be installed in the vicinity of the excavation hole 11, the sand pump 113 is moved to the vicinity of the construction position of each pile. According to the present embodiment, the sand pump 113 can be provided at a position separated from the excavation hole 11 as described above, so that the sand pump 113 is installed at one place. It becomes possible to construct with.

  In addition, although this embodiment demonstrated the case where the air in the plant side waste mud piping 112 which connects the sand pump 113 and the excavation hole 11 was removed, similarly, for example, the water etc. to which the suction pump was attached, etc. The present invention can also be applied to a case where air in the pipe is removed from the pipe through which the liquid flows. Furthermore, the present invention can be applied not only to removing air in a pipe through which liquid flows, but also to removing gas in a container that contains liquid.

DESCRIPTION OF SYMBOLS 10 Excavation system 11 Excavation hole 20 Stabilization liquid processing plant 30 Circulation switching device 31, 32 Piping 33, 34 Switching piping 35, 36, 37, 38 Stop valve 40 Excavator 41 Excavator main body 42 Rod 43 Bit 44 Piping 45 Rotation mechanism 100 Piping system 110 First piping system 111 Plant side mud piping 112 Plant side mud piping 113 Sand pump 114 Pump 120 Second piping system 150 Branch piping 151 Jet pump 152 Compressor 160 Discharge port 161 Suction port 170 Body 171 Air Supply port 172 Injection chamber 173 Ventilation port 174 Internal space

Claims (1)

An excavator that drills the ground to form an excavation hole, a stable liquid treatment plant that processes the recovered mud water to purify the stable liquid, and a feed for sending the stable liquid from the stable liquid treatment plant into the excavation hole. Drilling the excavation hole when constructing a cast-in-place pile comprising a mud pipe and a suction mud pipe provided with a suction pump in the middle and sending the stabilizing liquid in the excavation hole to the stabilizing liquid treatment plant A drilling system for
The mud feed pipe is connected to the excavator and the exhaust mud pipe is connected to the excavation hole, and the mud feed pipe is connected to the excavation hole and the exhaust mud pipe is connected to the excavator. Provided with a circulation switching device capable of switching between connected states,
A branch pipe is connected to the upper part of the mud pipe between the circulation switching device and the suction pump,
Compressed air is supplied from the compressor to the branch pipe, and the suction port of the jet pump that can generate an air flow from the suction port to the discharge port by blowing the compressed air in one direction is connected Excavation system characterized by being.

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